FILE - In this Feb. 14, 2017 file photo, Supreme Court Justice nominee Neil Gorsuch, center, accompanied by former New Hampshire Sen. Kelly Ayotte, right, arrives for a meeting on Capitol Hill in Washington, Tuesday, Feb. 14, 2017. Thirteen months after the death of Justice Antonin Scalia, the Senate is finally holding confirmation hearings to fill the vacancy, considering President Donald Trump’s choice of Gorsuch for the high court. Republicans refused even to grant a hearing to former President Barack Obama’s choice, but now the Senate will exercise its “advice and consent” role, a politically fraught decision with liberals pressuring Democrats to reject Gorsuch. A look at the process. (AP Photo/Andrew Harnik, File)

WASHINGTON (AP) — Thirteen months after the death of Justice Antonin Scalia, the Senate is finally holding confirmation hearings to fill the vacancy, considering President Donald Trump's choice of Neil Gorsuch for the high court.

Republicans refused to even grant a hearing to former President Barack Obama's choice, Merrick Garland, insisting the next president should decide. Now, the Senate will exercise its "advice and consent" role, a politically fraught decision with liberals pressuring Democrats to reject Gorsuch.

The Senate has confirmed 124 Supreme Court justices since the United States was founded.

The process is arduous, with dozens of one-on-one meetings with senators in recent weeks giving way to days of testimony starting Monday. Gorsuch and the Judiciary Committee's 20 members will give opening statements that day. Gorsuch will answer questions Tuesday and Wednesday, and outside witnesses will testify Thursday.

A look at the confirmation process, its rules, terminology and politics:

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WHAT DOES THE CONSTITUTION SAY

The Constitution lays out the process in just a few words, saying the president shall nominate Supreme Court justices "by and with the advice and consent of the Senate." Senate rules and tradition dictate the rest. President Donald Trump nominated Gorsuch, a judge on the Denver-based 10th U.S. Circuit Court of Appeals, on Jan. 31 and set the process in motion.

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THE PREPARATION AND DAY ONE

Gorsuch has met with 72 of the 100 senators in advance of his hearings. Like other nominees, he has participated in mock questioning facilitated by the Trump administration. These are sometimes dubbed "murder boards" because of their intensity.

On Monday, Gorsuch will have to sit through 10-minute statements from each of the 20 members of the committee, which will take several hours. After that, Gorsuch will finally speak, delivering his own 10-minute opening statement.

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THE QUESTIONS AND ANSWERS

In past hearings, the questions have centered around the nominee's legal qualifications, decisions as a judge, positions on political issues, interpretations of the Constitution, general legal philosophy and current legal controversies.

The stakes are high with any court pick, and especially now as confirmation of Gorsuch would ensure a conservative advantage on the court.

Gorsuch will face the same dilemma of many nominees before him — how to answer the questions clearly and concisely without weighing in on issues that could come before the Court or get himself in political trouble.

Democrats are likely to push him if he is reluctant. Senate Democratic leader Chuck Schumer of New York has already criticized him for deflecting questions when he asked him during their meeting whether Trump's immigration ban is constitutional.

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THE OTHER WITNESSES

The fourth and final day of the hearings, Thursday, will feature outside witnesses, usually former colleagues and advocacy groups who will testify for or against Gorsuch. In the past, one of the first to testify has been the chair of the American Bar Association's Standing Committee on the Federal Judiciary. That group has given Gorsuch a unanimous "well qualified" rating.

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THE COMMITTEE VOTE

By tradition, the committee will report the nomination to the Senate floor even if the majority of the panel opposes the nominee, so the full Senate can have the ultimate say. So instead of approving or rejecting the nominee, the committee will usually report the nomination favorably, unfavorably or without recommendation.

Of the 15 most recent nominations, 13 were reported favorably. Robert Bork, whose nomination was ultimately rejected by the Senate, was reported unfavorably in 1987; Clarence Thomas, who won confirmation, was reported without recommendation in 1991.

Gorsuch is expected to be reported favorably by the Republican-led committee.

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THE PROCEDURAL VOTES

Gorsuch is expected to have support from more than half the Senate, but getting to that vote will require several procedural maneuvers. Some Democrats have already said they will try to hold up the nomination, which means Senate Majority Leader Mitch McConnell, R-Ky., will have to hold a procedural vote requiring 60 votes to move forward.

Republicans have a 52-48 majority, so at least eight Democrats and independents will have to vote with Republicans. It's unclear whether Republicans will have those votes, meaning Democrats have the ability to block the nomination.

If the nomination is blocked, McConnell has another option. He could hold a vote to change the rules and lower the vote threshold. Former House Majority Leader Harry Reid, D-Nev., made a similar change for lower court nominations in 2013, a move called "the nuclear option." McConnell was extremely critical of that move but may have to do it if that's his last option to confirm Gorsuch.

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THE REAL VOTE

Once the Senate gets past procedural votes, it can hold a simple majority vote to confirm. In recent years, senators have sat at their desks during a Supreme Court vote and stood one by one to cast their votes. The votes have become more partisan over the years; the last unanimous vote was for Justice Anthony Kennedy in 1987.